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POHibernate: how do I code the mapping for a composite, unique key that isn't the primary key?
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  1. POHibernate: how do I code the mapping for a composite, unique key that isn't the primary key?
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    copied!<p>I have a file where I'm counting votes. I want to limit each user to a single vote on a given competition. The user can return and change his/her vote, but it would update the choice of competitor in the competition.</p> <p>I can't figure out how to do this using Hibernate mapping files. (The programming language is Java.)</p> <p>I've looked at using composite-id, but I want to have a typical numeric primary key on this thing if I need it later. (I also couldn't figure out how to make that work! =)</p> <p>Here's my mapping file from which I generate the model objects and SQL:</p> <pre><code>&lt;?xml version="1.0"?&gt; &lt;!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"&gt; &lt;hibernate-mapping&gt; &lt;class name="com.example.project.model.db.Vote" table="vote"&gt; &lt;id name="voteId" type="int"&gt; &lt;meta attribute="scope-set"&gt;protected&lt;/meta&gt; &lt;meta attribute="use-in-equals"&gt;true&lt;/meta&gt; &lt;generator class="native" /&gt; &lt;/id&gt; &lt;many-to-one name="user" column="userId" unique="false" not-null="true" lazy="false" class="com.example.project.model.db.User" /&gt; &lt;many-to-one name="competition" column="competitionId" unique="false" not-null="true" lazy="false" class="com.example.project.model.db.Competition" /&gt; &lt;many-to-one name="competitor" column="competitorId" unique="false" not-null="true" lazy="false" class="com.example.project.model.db.Competitor" /&gt; &lt;property name="dateAdded" type="date" not-null="true" /&gt; &lt;/class&gt; &lt;/hibernate-mapping&gt; </code></pre>
 

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